Wang Xuezhi, Lei Zhongfang, Zhang Zhenya, Shimizu Kazuya, Lee Duu-Jong, Khanal Samir Kumar
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; School of Resource and Environment, Anhui Agricultural University, Hefei 230036, China.
Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Sci Total Environ. 2023 Mar 10;863:160825. doi: 10.1016/j.scitotenv.2022.160825. Epub 2022 Dec 9.
An increasing attention has been paid to the secure and sustainable management of agricultural wastes, especially lignocellulosic biomass. Nanobubble water (NBW) contains 10-10 bubbles/mL with diameter <1000 nm. Although previous studies have examined the enhancement effects of NBW on methane production from organic solid wastes, the NBW-based anaerobic digestion (AD) system is still restrained from practical application due to the large increase in AD reactor volume, generation of wastewater, and increase in energy consumption as well. In this study, NBW bioaugmentation of anaerobically digested sludge for the first time was performed for high-solids AD of corn straw. Results show that cellulase, xylanases and lignin peroxidase activities were increased by 2-55% during the NBW bioaugmentation process. Significant enrichment of hydrolytic/acidogenic bacteria and methanogenic archaea were noticed in the NBW bioaugmented sludge. This study clearly demonstrated 47% increase in methane production from high-solids AD of corn straw when O-NBW bioaugmented sludge was applied, achieving a net energy gain of 5138 MJ/t-volatile solids of corn straw with an energy recovery of 34%. The NBW-based high-solids AD system can provide a novel and sustainable management solution for renewable energy production from agricultural wastes, targeting the reduction of environmental pollution and energy crisis.
农业废弃物，尤其是木质纤维素生物质的安全与可持续管理已受到越来越多的关注。纳米气泡水（NBW）含有10⁻¹⁰个/毫升直径小于1000纳米的气泡。尽管先前的研究已考察了纳米气泡水对有机固体废物甲烷产生的增强作用，但基于纳米气泡水的厌氧消化（AD）系统仍因厌氧消化反应器体积大幅增加、产生废水以及能耗增加而受限，无法实际应用。在本研究中，首次对厌氧消化污泥进行纳米气泡水生物强化，用于玉米秸秆的高固体厌氧消化。结果表明，在纳米气泡水生物强化过程中，纤维素酶、木聚糖酶和木质素过氧化物酶的活性提高了2%至55%。在纳米气泡水生物强化的污泥中，水解/产酸细菌和产甲烷古菌显著富集。本研究清楚地表明，当使用经O-NBW生物强化的污泥时，玉米秸秆高固体厌氧消化的甲烷产量增加了47%，实现了5138兆焦/吨玉米秸秆挥发性固体的净能量增益，能量回收率为34%。基于纳米气泡水的高固体厌氧消化系统可为农业废弃物可再生能源生产提供一种新颖且可持续的管理解决方案，目标是减少环境污染和能源危机。
